Last year I had lowered my 2004 Coupe all the way on factory bolts. I decided against getting an alignment done back then because I knew I was getting new tires and rims this past Spring so I figured I would wait. New tires and wheels were on the car for about a month prior to getting the alignment and the car has always driven true and straight since I bought it in Aug 2012.

Understanding that there is more to it that just driving straight, and wanting to protect my investment in new tires, I scheduled an appt with a local shop. "Before" specs were way off in nearly everything. "After" specs were all within spec using OEM specs. The only thing unchanged from the "before" to the "after" was the front Caster both left and right. It comes in at 5.6 degrees for both sides and should be between -0.5 degrees and 0.5 degrees. I don't think this particular shop had the equipment to adjust this.

My biggest concern now is the car pulling to the right. Is this due to the Caster being off, or due to the OEM specs on a lowered car? I was told by other forum users to go with OEM specs. I originally wanted to go with PFADT Street specs, but the shop doesn't deal with custom specs.

The receipt says they offer 30 days warranty on all work. I think I should try to get back in there and work it out with them. Any advice before I call them?

 

I had something similar happen. My car now drives straight but doesnt feel as planted as it did before it was realigned. I had it lowered on stock bolts like you and drove it that way for a couple weeks without issue (tracked straight, felt good). I had the shop use Pfadt street specs but upon comparing them, the street specs are very close to stock specs.

For your issue, car pulling to the right should be the toe in. Go back to them and they should adjust it accordingly.

 

I here this happen over and over again. The car was driving perfectly straight prior to the alignment and now, it is all over the place. The alignment was not done properly....period. You need to go back and have them fix it or go somewhere else.

I have found that unless you go to a specialized alignment shop (experience with sports cars), you have a 50% chance that it will not be performed properly. It's as simple as that. Do not go to Chevy dealers or tire places for alignments. You need to go to a proper performance shop that knows what they're doing.

 

I own an alignment shop. The caster number needs to be about .30* higher on right than left to not pull right. So 5.60 left and 5.90 right for instance. They have the ability to adjust caster because adjustment cams are in the lower control arms. The tech just isn't knowledgeable enough to understand what to do and set it to exact left and right. What we the after camber numbers? I would put them the same left and right. Go back and tell them to do what I wrote.

As far as custom specs go, they can do what needs you want. They just choose not to in case of tire wear. I do custom user specs anytime the customer wants. Usually those customers understand if it wears tires using their specs they own the tire wear issue.

 

Toe does not cause a pull. it will equal itself out going down the road. Only camber and caster cause a pull. Toe will only exacerbate one of the other angles.

 

The factory GM alignment specification has such a wide range that it's basically useless. GM published stupidly large ranges for the settings which lets some shops just put each corner within the published ranges leaving the alignment a mess.

You need everything to be the same left and right except for a bit more caster in the right front like mmr23 posted. The Pfadt street specs work fairly well.

 

Sorry to take so long to reply, needed to get back home from work and pull the papers. After Camber in the front was -0.2 on both sides. The before was -0.6 left and -0.9 right.

 

The shop I used actually put both sides just about exactly the same. Here are the specs on the printout.

Front Camber: -0.2 left, -0.2 right difference = 0.0
Front Caster: 5.6 left, 5.6 right difference = 0.0
Front Toe: .02 left, .03 right

Rear Camber: 0.1 left, -0.2 right difference = 0.3
Rear Toe: .03 left, -.02 right difference = 0.05

Total Toe: 0.01, Thrust Angle 0.02

 

Which is why it will pull right. Roads crown to the right to evacuate water form the road when raining. This crowning(lean) will make the car drift in that direction. Like I said have the caster about .30 higher on the right to offset that. Leave all else the same.

 

The front is OK except the caster but both rear tires are pointing the same direction and the left rear camber is wrong.

 

Here is your stock specs. Tell them to set the car to the numbers with right caster to 7.70. pm me and I'll give you my number so they can consult with me if they cannot.

front*
camber -0.20* +/- 0.50*
caster 7.40* +/- 0.50*
total toe 0.08* +/- 0.20*

rear
camber -0.18* +/- 0.50*
total toe -0.02* +/- 0.20*

 

If they just follow those numbers for each side independently then they could have between 0.3* to -0.7* camber on each corner. The front toe could change from 0.12* toe out to 0.28* toe in. Even keeping the same side to side those are big differences.

What do you want out of the car? Street driving? Aggressive in the corners?

Decent alignment numbers that don't cause much tire wear with lots of highway driving are something like this.
camber = -0.4* on each corner
toe = 0.02* toe in on each corner
caster = 7.5* to 8.5* range with a little more on the right as already mentioned.

There aren't many curvy roads around here so I run something like this. No pulling and the tire wear is very even.

Go a little more on the camber up to around -0.8* to -1.3* for more aggressive cornering but the trade off is more inside edge wear as the camber is increased. Some people also add a little more rear toe-in as they go more aggressive on the alignment.

 

Now you guys are really confusing me. I daily drive the car on the street, short local stop and go commutes 98% of the time. Hardly on the highways and no racing of any sort. I just want the car to drive straight again without fighting the wheel. Don't care about aggressive handling, cornering, etc...

This shop is not a pure alignment shop and does not specialize in sports cars. I chose them because they are conveniently located, fairly priced, treat me well for other routine maintanence services on my other cars, and wanted to give them a shot. Apparently the tech who did the work isn't as knowledgeable on this sort of work. I will give them a second chance to make it right, but realize they are going to stick with OEM specs or as close to it as possible.

 

Lionel I'll clarify. I want them to use the given specs. The first number in each line. Don't pay attention to the tolerances for each one.

Front
Camber -0.20 l/r
Caster 7.40 left 7.70 right
Toe 0.04 l/r

Rear
Camber -0.18 l/ r
Toe -0.01 l/r

Get as close as possible to those numbers. Again if you want pm me and I'll give you my personal number so they can talk to me.

I do plenty corvettes for forum members on here https://www.corvetteforum.com/southe...n-orlando.html

 

Yes, those numbers given would work for cruising.

The main point in the recommendations is keeping left and right the same except for the little extra right front caster.

The point I was making before is that if you look at the factory specs the tolerances are more than the target numbers by a large margin. With the tolerance, the GM specs are complete crap so the alignment could be complete crap if they just blindly set the car "within GM spec". The numbers could make sense with some clarification and direction on why to use a different rage, but I still can't figure out why they'd give you a range that allows positive caster or front toe-out for street driving.

 

i agree with you on this. it's up to the technician to want to spend the time to be accurate and do the right thing instead of just getting it close or "within tolerances".

all manufacturers give at least 1/2" tolerances. i've seen some as large as 1.25*. you have to give some "wiggle room". but again it's up to the technician to know what to do with that "wiggle room".

 

Thanks to both of you. I'm clear now what your asking. I'll print these out and get back to the shop. Hoping tomorrow.

 

c5 is one of the easiest cars in the world to align.

chances are they didn't do a crown compensation in the caster

why spend $200 at some "specialty shop" when firestone has the latest hunter laser rack?

you might have to baby sit the tech if you see something off but that's just an excuse to have the car aligned with you sitting in it

 

Gotta get my done, it's off since I had my TT bushings replaced, don't like the alignment they did at all car is " busy" feeling at speed, never was before, I'll try something like this and see how it feels...

 

Dan - if it's not too far Bennett in Cambridge has a flat drive-on rack and will do a good job with the alignment.